Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 17"

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RobyIndie
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by RobyIndie »

Hey man, me and a friend of mine kind of got it working! I need your help though, as the aspect ratio is way off, and the colours are way too dark.
Moreover, it doesn't work with a Gamecube although it kind of works with the SNES.
Care to check if we did anything wrong?
https://imgur.com/a/XsqMG
We removed the capacitors next to the Red, blue and green wires.
We tried with one capacitor on the sync line, then two, then zero (right now it's zero capacitors, because the current bypasses them and goes through the pink wire, that seemed to work best).
We also tried to ground the sync line in the scart plug, but it still doesn't work.

EDIT:For those of you wondering, my issue was a grounding issue. It works perfectly with no capacitors on the sync line, all I had to do was connect the audio ground pin from the scart plug to the general ground. I think the cable might be at fault, it seemed to be grounding everything through the audio ground pin for some reason.
I adjusted the aspect ratio without any problems through the service menu. Just remember to do it two times if you're in Europe like me! One for 50 Hz one for 60 Hz!
Last edited by RobyIndie on Wed Sep 27, 2017 8:20 pm, edited 3 times in total.
xAzurexEonx
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by xAzurexEonx »

Have you noticed any color differences between the JVC.

Red and brown stand out differently between the two I have.

The easiest way to tell it is off, is by pushing one of your control buttons and seeing the difference in the orange color.

I did go through every menu and matched all settings from the monitor I prefer.
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soviet9922
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by soviet9922 »

Robbie PMed me about his issue, and was bad grounding he fixed it.

When you build your rgb mod and solder the female plug on the monitor, is best to solder all ground pins on the scart connector.
If you use just one you are at risk of getting any scart random lead for some console that also is not properly grounded, for example you ground just the sync ground and your cable have only audio ground.

So as result you got a very dark picture and poor contrast.
Esprit
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by Esprit »

Wow, this is amazing work.
I have JVC TM-H140PN, which is appears to be very similar to TM-H1700G. To make it accept RGB I need:
- Connect R,G and B cabels to ANA-R, ANA-G and ANA-B (pins 33-35)
- Connect ground to pvm ground. Is D-GND (pin 26) good for that?
- Sync to Y1/SYNC IN (pin 15)
- Put 0.75+V on YS2 (pin 32) to force PVM to pass RGB image as Input B
- Remove capacitors connected to pins 33-35 (C517-519) and resistor from pin 32 (R559).
Is this correct?

Image Image Image

Here is full JVC TM-H140PN Service Manual with circuit diagrams.

UPDATE 1;
Well, I did as I show and it didn't work. It only outputs B/W composite picture from pin 15. It didn't react on voltage on YS2. What I did wrong?
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holaplaneta
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by holaplaneta »

Would there be a way of using one of these to make the process easier?

https://www.ebay.com/itm/JVC-monitor-SC ... 3369298498

Like soldering directing to this board... or making the slot male adapter?
zgba
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by zgba »

Hi there, I've been a long time reader of this forum, but only recently I started tinkering with my TM-H1700G. Here's the story in a nutshell:

I wanted to check if re-soldering missing channel selector buttons and resistors would suffice to fool this monitor to think, that it's a TM-H1750G. I did that only to find out, that even if the PCBs are the same between the models I mentioned, there must be a difference or two in microcontroller's firmware. Ok, let's drop that. Nevertheless I was pretty sure that you can use the existing circuitry to inject an RGB signal into the jungle IC. After studying the datasheet I could only confirm my suspicions.

Before I even attempted to connect the signals to the jungle IC, I started looking for the TM-H1750G manual, but AFAIK there's no such thing to be found in the internets. Fortunately, I have found the TM-H150CG datasheet which is similar enough for my needs. The signal path from the extension port to the jungle goes through two transistor buffers. I started thinking about constructing a contraption made of missing transistors and IF-01COMG expansion board protection circuitry, but then (this is where the story begins) I found this post. To see if it would work for me I have soldered filter caps and termination into the scart socket and connected the thing to the mainboard. Of course I have removed three caps from each signal line to the ground (C531-C533) and R554 tying YS2 to ground. Unfortunately what I'm getting is a rather wavy colour image with some heavy colour bleeding and very jagged edges. What am I doing wrong?

RGB signals are connected through 100nF clamp capacitors with 75R termination, sync signal is feeded through 100nF cap as well. Both R, G, B and sync grounds are tied together and connected to analog (probably) ground on the main PCB.

Any suggestions?
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Star1
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by Star1 »

Did you not use 30 ohm resistors in line with each color signal? The jungle IC expects 0.5v peak to peak, so you need those resistors to lower the signal.
zgba
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by zgba »

Not when I was writing my previous post. Now I got them installed (33R ones were the closest I could find in my stash), but that didn't change a bit.
That's how it looks right now:
Image
And that's the 'circuit':
Image
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Star1
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by Star1 »

You could try another cap value for the sync line, like Soviet had to do. I used 0.1 with success, but for him that resulted in a wavy image. Also, the series resistors should go before the caps.
zgba
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by zgba »

I tried a bunch of different values ranging from 10nF to 68nF and it seems that 47nF is the best option, although not perfect:

Image

As you can see there's a slight misplacement on the right edge. Not acceptable.

I hooked up another console (PS2) and it looked almost perfect. Some artifacts in big red shapes for example. PS2 outputs another type of sync IIRC, so I even changed the sync in my SNES cable from composite to csync - no visual change.

I took a break and then thought about someting different - not attaching sync line directly to the Jungle IC, but going through the composite input. It didn't work at the beginning (picture was scrolling horizontally), but then I realized that I'm feeding the sync signal through the bypass cap, which - when removed - seemed to solve my sync problem for good. Now I have to hook up different consoles and see if the overall picture quality is decent or if I have to tweak colour lines some more.

Thanks for help, I will post some more pics once I'm done for good.

BTW I don't think that the order of series cap/resistor in R, G and B lines would make any difference.
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Syntax
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by Syntax »

zgba wrote: BTW I don't think that the order of series cap/resistor in R, G and B lines would make any difference.
The order is critical and thats why your 30R did nothing. You set it up as a current limiter not a voltage divider.

Order for RGB lines should be

Console-30R(inline)-75R(to ground)-100n cap-Jungle

Choosing values for these .5vpp mods can be a pain if you worry too much about it.

A Genesis should use a 60R resistor http://tinyurl.com/y76ejps8

A 1 chip SNES should us a 39R http://tinyurl.com/y7bfr97v

A 3 chip SNES should use a 55R http://tinyurl.com/y9ov7oxc

(press RESET to start the sim)

Really most of these old chips can handle up to 1vpp with no clipping, but its best to keep it under .7vpp so you have more room to play with brightness settings.
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holaplaneta
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by holaplaneta »

It would be awesome is somebody could do a video tutorial on youtube about how to do this right...
zgba
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by zgba »

Looks like my current setup works just fine, problems I encountered were connected to the sync line, not colour lines. I will post some more information once I'm done with the mod.
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holaplaneta
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by holaplaneta »

Excellent, thanks. Keep on posting, the more info we have about possible fixes and variants to this mod the better.

I might get some H1900G soon and I really want to do this mod on them. I may actually do a video at the end if everything goes well.

Cheers.
sunomo
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by sunomo »

Hi everyone, I have a TM-H1700CG and a TM-H1900G and I'm trying to to make this RGB mod. As video source I use Megadrive and SNES.

I've no issue on TM-H1900G but I'm struggling to get a good result on TM-H1700CG. The image is like dragged to the right. Not only on the right edge, all the colors are overlapped. It's very noticeable in the grid pattern. Here a few pictures of TM-H1700CG:

Image Image Image

On TM-H1900G I use 473 cap for the sync line and 104 cap for the RGB lines. As resistors for the RGB lines both 30 and 33 ohms work. 75 ohms to the ground. On TM-H1700CG I've tried the same circuit. I've also tried to change the cap on the sync line back to the 104 cap, but without improvement. Any suggestion?
zgba
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by zgba »

Hi, I'm not an expert, but I've managed to get rid of my problems with the sync line after feeding the sync signal directly to the composite input. Another hint would be to check your RGB cable, maybe it's missing the caps that remove the DC offset?
sunomo
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by sunomo »

Hi, the previous issue on TM-H1700CG was due to the fact I simply forgot to remove the caps near the RGB lines. Removing them I fixed it.

Now I'm still working on TM-H1900G, since I've troubles with SNES. I used 473 cap for the sync line and with MegaDrive the image was centred and almost perfect. However with SNES still had irregular shape. I tried different caps but nothing. Then I tried to feed the sync signal into the composite line.

The point is that by doing so the image looks perfect in shape and colors, but it's noticeably shifted on the left. I set the geometry in the menu H.POS +5 but still shifted (pictures)

Image Image

I've no idea what I could try, anyone else noticed this problem?
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Star1
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by Star1 »

Do you mean the quick menu, or the service menu?
sunomo
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by sunomo »

It was the Service Menu, useless.

Anyway I overcame the problem by injecting the Sync not at the beginning of Line A or Line B but in the middle of the input board. By doing so, you don't have to worry about any cap on the sync line or any switch on the back. Everything is managed by the existing input signal board and it works perfectly with SNES, MegaDrive, NeoGeo... don't have anything else to test. Borders are always straight and pictures always centered.

Image

Let me also say that I've not added any Scart or BNC plug on the back. I thought, we have 4 unused BNC on the back for Composite In and Out, why don't exploit them to take the RGB into this monitor? So I did. I cut the connection between In and Out and the connection between In and Input Board. Audio and S-Video are still working. No Switches, very clean.

Image Image

Thanks to everyone who posted here, you inspired and helped me a lot :)
darkcrono
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by darkcrono »

soviet9922 wrote:Hacking RGB onto the H1700G is more or less the same, the only difference is that is required is connecting the YS2 line to 0.80+ t, because the front switch selector is not present.
Also the cap placement in the jungla is different, and they are 3 caps in the RGB lines to ground so they don't float i suppose, also a 0 ohm resistor on YS2 to pull it low, they must be removed.
Image
Keep the same setup that in my other monitor a DPDT switch having composite to jungla pin 15 and as option to the composite jack.
Also another switch to turn YS2 blanking on or off so i can keep using composite and svideo.
Hi i'm trying to make this mod to a 1900g but i don't quite understand the YS2 thing, where do i have to connect it? is there somewhere in the pcb silkscreened the YS2?
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evilsim
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by evilsim »

I've just picked up 4 x JVC TM-A101G and 1 x TM-1051DG

I have yet to open them up, but it would be nice to RGB mod them. The manual says theyre 250 line horizontal so should look ok, good for testing consoles etc. I'll crack them open soon and check their jungle IC.

If anyone has a service manual or had experience with these little 10" models, please comment or flick me a PM.

I followed the guides on this site to RGB mod my TM-19xx model which I think looks better than my 20" Sony PVM's (fat scanlines are just glorious) ! But have since gone and bought the replica card as it also supports YPbPr.


edit: the TM-1051DG looks to be promising, have not checked/opened a TM-A101G yet.
TM-1051DG Jungle http://pdf.datasheetcatalog.com/datashe ... a/2711.pdf
Looks like the TM-H150CG circuitry!

edit: Hey darkcrono -- you need to solder a wire between the two Purple dots shown in that picture (thats it !). If you put a switch in the middle of said wire, this will enable/disable fastblanking and allow you to either use RGB analogue input or the factory composite/S-video if you want to. Hope this helps.
darkcrono
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by darkcrono »

thanks evilsim i somehow skip that by the moment, but i realized couple days ago.

:oops:
darkcrono
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by darkcrono »

So i started modding the 1900g and soldered scart pins 15,11,7 for rgb, 13,9,5 for grounds, and the sync via pin 20, sync ground 18, and only get b/w picture in composite, same as esprit, any idea whats going on?

Measured the voltage from c129 to ground, 0.9v, why isn't it forcing the rgb?

Image
Image
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soviet9922
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by soviet9922 »

Hi darkcrono, seems from the picture b/w composite video, you are not enabling blk on the jungle IC so it's not displaying the RGB signal from the inputs.

You have to check how much +V is going to BLK pin it's probably not correctly and RGB it's not enabled.
darkcrono
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by darkcrono »

Thanks for answering, the measured voltage to ys2 from c129 is 0.925v.

Is it too high for it to activate?
CLickCLK
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by CLickCLK »

Hello all. i'm trying to rgb mod tm-h150cg, but can't get it to work. I'm a total noob at rgb (I didn't even knew that rgb or professional video monitors even existed until last summer), so I don't quite understand what I'm doing yet.

I did everything like in the first post of this thread, built a board with 33ohm and 75ohm resistors and 0.1u capacitors, soldered rgb and sync to jungle ic pins, removed capacitors from rgb lines, added a jumper from pin 12 of external board connector to gnd, attached scart connector, also added audio line to pin 2 of external board connector (audio working ok). I don't have any device with rgb cable, so I built a cable myself for sega mega drive 2 using this diagram

Image

, except I didn't connect +5v to pins 8 and 16 of scart, because this are not used in monitor.

I got no picture at all, but if I switched to input A or B then I got unstable black and white picture. Next I tried to get sync straight from CSYNC (pin 5 of megadrive connector) - still no picture, not even B/W at inputs A or B. I tried to add 470 ohm resistor and 220uf capacitor to sync, as said here https://www.retrorgb.com/csync.html (soldered in this order: console->470 ohm resistor to positive side of 220uf capacitor->negative side of capacitor to scart, and also tried console to positive side of capacitor->negative side of capacitor to resistor->scart), but still got nothing.

My genesis console is a clone, but good one and should support rgb, but I thought maybe it was the problem, so I tried to connect PSX, using this schematic
Image

and, as always, I got nothing. Tried to get pure CSYNC using the method described in the first post of this thread: https://assemblergames.com/threads/ps1- ... elp.56631/ ( lifted pin 20 of CXA1645, soldered a wire from point marked in that post as "csync before 2.2k resistor" to the pad where pin 20 of CXA1645 used to be) - also nothing. Tried with 75 ohm resistor and 220uf capacitor on sync line - nothing, with 470 ohm resistor and 220uf capacitor - still nothing.

I really need some help. What am I doing wrong? Is it some error on the monitor side of things or I built incorrect cables or something else? I triple checked all the wiring and found no errors, at least on monitor side.

Here's some photos of my installation (see under spoiler):
Spoiler
Image

Image

Image

Image

Image

Image
darkcrono
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by darkcrono »

From what i know if you have a model compatible with ext cards, you should switch to channel "D", but i dont own that model and cant really say, also you sould try a rgb cable known working to narrow down the culprit
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Star1
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by Star1 »

CLickCLK wrote:Hello all. i'm trying to rgb mod tm-h150cg, but can't get it to work. I'm a total noob at rgb (I didn't even knew that rgb or professional video monitors even existed until last summer), so I don't quite understand what I'm doing yet.

I did everything like in the first post of this thread, built a board with 33ohm and 75ohm resistors and 0.1u capacitors, soldered rgb and sync to jungle ic pins, removed capacitors from rgb lines, added a jumper from pin 12 of external board connector to gnd, attached scart connector, also added audio line to pin 2 of external board connector (audio working ok).
I'd really try the rgb cable on another set, just to rule out the cable from the console having issues. Also, your board has the same mistake as earlier in the thread. The caps need to be after the resistors. As Syntax said, the order is critical. first a 33 ohm in-line, then 75 ohm to ground, then a resistor.
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Star1
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by Star1 »

darkcrono wrote:Thanks for answering, the measured voltage to ys2 from c129 is 0.925v.

Is it too high for it to activate?
It should be just fine, but tell me, did you remove the capacitors, and resistors as per the guide? I can't really tell from the images.
CLickCLK
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Re: Hacking RGB into a jvc TM-H150cg 15" and JVC TM-H1700G 1

Post by CLickCLK »

Star1 wrote: I'd really try the rgb cable on another set, just to rule out the cable from the console having issues. Also, your board has the same mistake as earlier in the thread. The caps need to be after the resistors. As Syntax said, the order is critical. first a 33 ohm in-line, then 75 ohm to ground, then a resistor.
So it must be tm-h150cg mainboard->in line 33 ohm resistor -> 75ohm resistor to gnd and 0.1uf in-line cap->scart connector or tm-h150cg mainboard->in-line 0.1uf cap->in-line 33 ohm resistor-> 75 ohm resostor to gnd and to scart connector?
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